Organic electronics has been an intense research topic over the last two decades or so because of their enormous commercial potential. Some illustrative organic electronic devices are diodes, organic thin film transistors, and organic photovoltaics. One of the key components in these devices is organic semiconductors which have received extensive research and development efforts. In the field of organic electronics, organic thin film transistors (OTFTs) have in recent years attracted great attention as a low-cost alternative to mainstream amorphous silicon-based transistors for electronic applications. OTFTs are particularly suited for applications where large-area circuits (e.g., backplane electronics for large displays), desirable form factors and structural features (e.g., flexibility for “electronic paper”), and affordability (e.g., ultra low cost for ubiquitous radio frequency identification tags) are essential.
Organic semiconductors are typically based on: (1) acenes such as tetracene, pentacene and their derivatives, (2) thiophenes such as oligothiophenes and polythiophenes, (3) fused-ring thiophene-aromatics and thiophene-vinylene/arylene derivatives. Most of these semiconductors are either insoluble in common organic solvents or sensitive to air, and are therefore not suitable for fabricating low-cost OTFTs via liquid patterning and deposition processes under ambient conditions. There is therefore a critical need addressed by embodiments of the present invention to develop liquid-processable and air stable organic semiconductor compounds to enable low-cost OTFTs.
The following documents provide background information:
Christos D. Dimitrakopoulos et al., “Organic Thin Film Transistors for Large Area Electronics,” Adv. Mater., Vol. 14, No. 2, pp. 99-117 (2002).
Salem Wakim et al., “Organic Microelectronics: Design, Synthesis, and Characterization of 6,12-Dimethylindolo[3,2-b]Carbazoles,” Chem. Mater. Vol. 16, No. 23, pp. 4386-4388 (published on web Jul. 7, 2004).
Nan-Xing Hu et al., “5-11-Dihydro-5,11-di-1-naphthylindolo[3,2-b]carbazole: Atropisomerism in a Novel Hole-Transport Molecule for Organic Light-Emitting Diodes,” J. Am. Chem. Soc., Vol. 121, pp. 5097-5098 (1999).
Ong et al., U.S. Pat. No. 6,949,762
Hu et al., U.S. Pat. No. 5,942,340.
Hu et al., U.S. Pat. No. 5,952,115.
Hu et al., U.S. Pat. No. 5,843,607.